The objective of the proposed research is the determination of the commonalities, differences, and interactions with respect to the comsumption of cigarettes and coffee. Under conditions of 10-day residences in a programmed laboratory environment which provides for continuous and comprehensive observations of individual and social activities both required (e.g., recurrent health and mood assessments) and optimal (e.g., social meals), instances and magnitude of such poly-substance use will be determined for three-person groups in relationship to a broad range of environmental circumstances (e.g., work, leisure, learning, eating, socializing, etc.) and motivational influences (e.g., appetitive and avoidance contingencies of reinformcement) typically involved in everyday life pursuits. Potentially interactive relationships between cigarette smoking and coffee drinking habits will be assessed under conditions of counter-balanced abstinence schedules which will additionally provide the opportunity to observe effects of substance-free and substance-controlled periods on collateral and individual and social non-drug-seeking behaviors.